Dada is not an art style, but an antimilitaristic and antiaesthetic attitude.
The movement (in both art and literature) came out of the period just after World War I, starting in Zurich. It was a reaction to the destruction of which man was now capable through technology as well as a rejection of accepted canons of morality and taste. The spirit of Dada can be seen in the works of Duchamp, Man Ray, Hoch, Miro, and Picasso.
The works of these artists were not met with enthusiasm at the time, but now are considered some of the most important works of twentieth century art.